Project II seeks to develop the finding that a single clone of murine IgM is pathogenic for intestinal reperfusion injury in antibody-deficient animals. The first aim will be to determine whether this antibody binds to definable antigens in murine tissue, whether injured or not. This investigation may lead to discovery of the identity of the murine antigen. In parallel, studies of human peritoneal B lymphocytes will be initiated in an attempt to determine whether the products of these cells have activity which is similar to the activity of the monoclonal IgM. Finally, support with histochemistry and complement assays will be given to other Projects within the Trauma Center.